Libav could be made to crash or run programs as your login if it opened aspecially crafted file.

==========================================================================
Ubuntu Security Notice USN-1790-1
April 04, 2013
libav vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 12.10
- Ubuntu 12.04 LTS
Summary:
Libav could be made to crash or run programs as your login if it opened a
specially crafted file.
Software Description:
- libav: Multimedia player, server, encoder and transcoder
Details:
It was discovered that Libav incorrectly handled certain malformed media
files. If a user were tricked into opening a crafted media file, an
attacker could cause a denial of service via application crash, or possibly
execute arbitrary code with the privileges of the user invoking the
program.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 12.10:
libavcodec53 6:0.8.6-0ubuntu0.12.10.1
libavformat53 6:0.8.6-0ubuntu0.12.10.1
Ubuntu 12.04 LTS:
libavcodec53 4:0.8.6-0ubuntu0.12.04.1
libavformat53 4:0.8.6-0ubuntu0.12.04.1
This update uses a new upstream release, which includes additional bug
fixes. In general, a standard system update will make all the necessary
changes.
References:
http://www.ubuntu.com/usn/usn-1790-1
CVE-2013-0894, CVE-2013-2277, CVE-2013-2495, CVE-2013-2496
Package Information:
https://launchpad.net/ubuntu/+source/libav/6:0.8.6-0ubuntu0.12.10.1
https://launchpad.net/ubuntu/+source/libav/4:0.8.6-0ubuntu0.12.04.1